Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 200048 AFDJKL Area Forecast Discussion National Weather Service Jackson KY 848 PM EDT THU MAY 19 2016 .UPDATE...
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Issued at 848 PM EDT THU MAY 19 2016 Forecast looks on track. Updated hourly NDFD for latest observational trends, but there were no changes to overall forecast.
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&& .SHORT TERM...(This evening through Friday night) Issued at 400 PM EDT THU MAY 19 2016 19z SFC analysis shows high pressure moving through the northern Ohio Valley while low pressure is developing to the south. This SFC pattern has kept the skies mostly clear through eastern Kentucky while also supporting northeast winds at between 5 to 10 kts with gusts up to 15 kts. Despite the increased sunshine, temperatures only made it to the mid 60s for most of the area (or about 10 degrees below normal), though some readings near 70 degrees are noted along the Tennessee border. Meanwhile, dewpoints varied from the mid 40s northwest to the upper 40s and low 50s in the far south. The models are in good agreement aloft through the short term as they all take the weak ridging currently overhead off to the east overnight allowing a developing trough to spread into the Ohio Valley on Friday. This trough will bring with it plenty of energy at mid levels and start to even deepen heading into Saturday morning. Given the model agreement have not deviated much from a general blend solution though did lean more heavily on the HRRR and NAM12 for weather details. sensible weather will feature a night of increasing clouds from the southwest but probably not before a small to moderate ridge to valley temperature split sets up later this evening. However, the clouds should be enough by dawn to make for more uniform temperatures by 12z. About that time, a shield of rain showers will start to overspread East Kentucky as an inverted trough makes its way into to the Tennessee Valley. This may also allow enough instability to develop for a stray thunderstorm or two to develop Friday afternoon. In addition, heavy rains will be possible as this wave moves through on Friday into the first part of Friday night. Will continue to highlight this concern in the HWO. Expect the clouds and rain to keep temperatures fairly uniform on Friday and Friday night. Used the ShortBlend as a starting point for most elements of the forecast with some adjustments early on for terrain induced temperature differences. During the latter part of the forecast the SuperBlend was used to initialize the forecast with adjustments made mainly to hedge the PoPs more toward the specifics of the NAM12 guidance with the higher MAV MOS values most similar Friday and Friday night. .LONG TERM...(Saturday through Thursday) Issued at 340 PM EDT THU MAY 19 2016 Model agreement is decent to good with larger scale features. There are a few differences beginning to crop up with respect to timing and strength of minor impulses embedded in nearly zonal mid level flow during the latter portion of the extended. In general these features are responsible for adding a bit of uncertainty to the last 36 to 48 hour of the extended. A significant mid/upper level trough will be making it`s way through the Great Lakes-Ohio Valley Region Saturday. At about the same time shortwave energy will begin its journey through the base of the main trough...digging as far south as the Florida peninsula by Sunday. Mid and upper level ridging will build into the region by Monday and then flatten out into a more zonal flow regime for the remainder of the extended. For sensible weather, we can expect a wet start to the extended with the threat of showers lingering into at least the first half of the upcoming weekend. Continued to advertise a more optimistic, dry forecast for Sunday per model/guidance consensus. But the operational ECMWF has consistently hinted at the potential of a few isold showers over the higher terrain to the south and east Sunday. Ridging aloft will provide generally fair weather through the first half of the week. But minor disturbances combined with diurnal heating should allow for at least a chance of rain to creep back into the forecast by late Tuesday night and thereafter. Model forecast soundings continue to show increasing sfc based instability for the same time frame, warranting the mention of thunder from Tuesday night forward. Still seeing an increasing trend in temps through the period with temperatures warming to around 80 for daily highs from Tuesday through to the end of the week. Overnight lows will continue to run cool until mid week when they also warm to above normal level, generally in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 738 PM EDT THU MAY 19 2016 VFR conditions will prevail until after daybreak on Friday. However, low pressure moving northeast from the lower MS valley towards KY will bring lowering clouds Friday, with rain spreading across the area from southwest to northeast during the day. MVFR conditions will impact SME and LOZ first on Friday, but by late afternoon all TAF sites should be experiencing MVFR conditions. Conditions will continue to deteriorate Friday night with widespread IFR or worse conditions expected. && .JKL Watches/Warnings/Advisories... None. && $$ UPDATE...SBH SHORT TERM...GREIF LONG TERM...RAY AVIATION...SBH is the U.S. government's official web portal to all federal, state and local government web resources and services.